Description
Original diagnose after Shimada (2007) p. 513 [2178]: Small lamnoid teeth (holotype as the largest specimen measuring 6 mm in total tooth height) consisting of tall crown (variably inclined distally), well-marked tooth neck, and massive root, with the following combination of characters: osteodont tooth histology (note absence of pulp cavity in Figure 1F); crown triangular in labial and lingual views, with pointed tip and sprawling base (except along the labial side); crown tip strongly directed lingually, giving hook-like appearance; mesial and distal cutting edges weak and blunt towards to apex and base of crown, and absent at mid-portion of crown outlining nearly perfect circle in transverse cross-section; crown surfaces smooth; lingual crown face strongly convex and labial face moderately convex; basal margin of crown gently convex or concave on labial face and broadly and deeply concave on lingual face (particularly noticeable in mesial and distal views); labiolingual length and mesiodistal length at crown base about equal; root massive and short apicobasally, with deep nutritive groove that bisects pronounced lingual protuberance and may possess prominent nutritive pore near center of the groove; apical face of lingual protuberance flat or weakly convex; basal face of each root lobe flat or weakly convex; and labiomesial corner of root labially pointing and labiodistal corner blunt and rounded. Mesiodistally oriented, low heel may occur at mesial and distal extremities of crown base along labial margin. Differing from teeth of Megachasma pelagios in possessing prominent nutritive groove that deeply bisects root longitudinally from the top of the lingual root protuberance.

Remarks
shark-references Species-ID=3604;
valid after Shimada (2007) p. 513 [2178];

synonym of Pseudomegachasma comanchensis after Shimada et al. (2015) [22941];

References